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Are Heavy Fermion Strange Metals Planckian? CRYSTALS 2022; 12:251. [PMID: 35910592 PMCID: PMC8979306 DOI: 10.3390/cryst12020251] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 02/10/2022] [Indexed: 11/22/2022]
Abstract
Strange metal behavior refers to a linear temperature dependence of the electrical resistivity that is not due to electron–phonon scattering. It is seen in numerous strongly correlated electron systems, from the heavy fermion compounds, via transition metal oxides and iron pnictides, to magic angle twisted bi-layer graphene, frequently in connection with unconventional or “high temperature” superconductivity. To achieve a unified understanding of these phenomena across the different materials classes is a central open problem in condensed matter physics. Tests whether the linear-in-temperature law might be dictated by Planckian dissipation—scattering with the rate ∼kBT/ℏ—are receiving considerable attention. Here we assess the situation for strange metal heavy fermion compounds. They allow to probe the regime of extreme correlation strength, with effective mass or Fermi velocity renormalizations in excess of three orders of magnitude. Adopting the same procedure as done in previous studies, i.e., assuming a simple Drude conductivity with the above scattering rate, we find that for these strongly renormalized quasiparticles, scattering is much weaker than Planckian, implying that the linear temperature dependence should be due to other effects. We discuss implications of this finding and point to directions for further work.
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2
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Iron pnictides and chalcogenides: a new paradigm for superconductivity. Nature 2022; 601:35-44. [PMID: 34987212 DOI: 10.1038/s41586-021-04073-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 09/29/2021] [Indexed: 11/09/2022]
Abstract
Superconductivity is a remarkably widespread phenomenon that is observed in most metals cooled to very low temperatures. The ubiquity of such conventional superconductors, and the wide range of associated critical temperatures, is readily understood in terms of the well-known Bardeen-Cooper-Schrieffer theory. Occasionally, however, unconventional superconductors are found, such as the iron-based materials, which extend and defy this understanding in unexpected ways. In the case of the iron-based superconductors, this includes the different ways in which the presence of multiple atomic orbitals can manifest in unconventional superconductivity, giving rise to a rich landscape of gap structures that share the same dominant pairing mechanism. In addition, these materials have also led to insights into the unusual metallic state governed by the Hund's interaction, the control and mechanisms of electronic nematicity, the impact of magnetic fluctuations and quantum criticality, and the importance of topology in correlated states. Over the fourteen years since their discovery, iron-based superconductors have proven to be a testing ground for the development of novel experimental tools and theoretical approaches, both of which have extensively influenced the wider field of quantum materials.
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Kim H, Shim JH, Kim S, Park JH, Kim K, Min BI. Unusual Pressure-Induced Quantum Phase Transition from Superconducting to Charge-Density Wave State in Rare-Earth-Based Heusler LuPd_{2}In Compound. PHYSICAL REVIEW LETTERS 2020; 125:157001. [PMID: 33095605 DOI: 10.1103/physrevlett.125.157001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 03/10/2020] [Accepted: 09/10/2020] [Indexed: 06/11/2023]
Abstract
We investigate the pressure effects on the electronic structures and phonon properties of rare-earth-based cubic-Heusler compound LuPd_{2}In, on the basis of ab initio density functional theory. We find the occurrence of intriguing phase transition from the superconducting (SC) to charge-density wave (CDW) state under pressure (P), which is quite unusual in that the pressure is detrimental to the CDW state in usual systems. The SC transition temperature T_{C} of LuPd_{2}In increases first with increasing pressure, up to P_{C}≈28 GPa, above which a quantum phase transition into the CDW state takes place. This extraordinary transition originates from the occurrence of phonon softening instability at a special q=M in the Brillouin zone. We thus propose that LuPd_{2}In is a quite unique material, in which the CDW quantum critical point is realized under the SC dome by applying the pressure.
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Affiliation(s)
- Heejung Kim
- Department of Physics, POSTECH, Pohang 37673, Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Korea
| | - J H Shim
- Department of Physics, POSTECH, Pohang 37673, Korea
- Department of Chemistry, POSTECH, Pohang 37673, Korea
| | - Sooran Kim
- Department of Physics Education, Kyungpook National University, Daegu 41566, Korea
| | - Jae-Hoon Park
- Department of Physics, POSTECH, Pohang 37673, Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Korea
- Division of Advanced Materials Science, POSTECH, Pohang 37673, Korea
| | - Kyoo Kim
- Department of Physics, POSTECH, Pohang 37673, Korea
- MPPHC-CPM, Max Planck POSTECH/Korea Research Initiative, Pohang 37673, Korea
- Korea Atomic Energy Research Institute (KAERI), 111 Daedeok-daero, Daejeon 34057, Korea
| | - B I Min
- Department of Physics, POSTECH, Pohang 37673, Korea
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4
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Wang Y, Walter E, Lee SSB, Stadler KM, von Delft J, Weichselbaum A, Kotliar G. Global Phase Diagram of a Spin-Orbital Kondo Impurity Model and the Suppression of Fermi-Liquid Scale. PHYSICAL REVIEW LETTERS 2020; 124:136406. [PMID: 32302177 DOI: 10.1103/physrevlett.124.136406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/28/2020] [Indexed: 06/11/2023]
Abstract
Many correlated metallic materials are described by Landau Fermi-liquid theory at low energies, but for Hund metals the Fermi-liquid coherence scale T_{FL} is found to be surprisingly small. In this Letter, we study the simplest impurity model relevant for Hund metals, the three-channel spin-orbital Kondo model, using the numerical renormalization group (NRG) method and compute its global phase diagram. In this framework, T_{FL} becomes arbitrarily small close to two new quantum critical points that we identify by tuning the spin or spin-orbital Kondo couplings into the ferromagnetic regimes. We find quantum phase transitions to a singular Fermi-liquid or a novel non-Fermi-liquid phase. The new non-Fermi-liquid phase shows frustrated behavior involving alternating overscreenings in spin and orbital sectors, with universal power laws in the spin (ω^{-1/5}), orbital (ω^{1/5}) and spin-orbital (ω^{1}) dynamical susceptibilities. These power laws, and the NRG eigenlevel spectra, can be fully understood using conformal field theory arguments, which also clarify the nature of the non-Fermi-liquid phase.
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Affiliation(s)
- Y Wang
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - E Walter
- Arnold Sommerfeld Center for Theoretical Physics, Center for NanoScience, and Munich Center for Quantum Science and Technology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - S-S B Lee
- Arnold Sommerfeld Center for Theoretical Physics, Center for NanoScience, and Munich Center for Quantum Science and Technology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - K M Stadler
- Arnold Sommerfeld Center for Theoretical Physics, Center for NanoScience, and Munich Center for Quantum Science and Technology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - J von Delft
- Arnold Sommerfeld Center for Theoretical Physics, Center for NanoScience, and Munich Center for Quantum Science and Technology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - A Weichselbaum
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
- Arnold Sommerfeld Center for Theoretical Physics, Center for NanoScience, and Munich Center for Quantum Science and Technology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - G Kotliar
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08856, USA
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5
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Yi M, Frano A, Lu DH, He Y, Wang M, Frandsen BA, Kemper AF, Yu R, Si Q, Wang L, He M, Hardy F, Schweiss P, Adelmann P, Wolf T, Hashimoto M, Mo SK, Hussain Z, Le Tacon M, Böhmer AE, Lee DH, Shen ZX, Meingast C, Birgeneau RJ. Spectral Evidence for Emergent Order in Ba_{1-x}Na_{x}Fe_{2}As_{2}. PHYSICAL REVIEW LETTERS 2018; 121:127001. [PMID: 30296157 DOI: 10.1103/physrevlett.121.127001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 07/05/2018] [Indexed: 06/08/2023]
Abstract
We report an angle-resolved photoemission spectroscopy study of the iron-based superconductor family, Ba_{1-x}Na_{x}Fe_{2}As_{2}. This system harbors the recently discovered double-Q magnetic order appearing in a reentrant C_{4} phase deep within the underdoped regime of the phase diagram that is otherwise dominated by the coupled nematic phase and collinear antiferromagnetic order. From a detailed temperature-dependence study, we identify the electronic response to the nematic phase in an orbital-dependent band shift that strictly follows the rotational symmetry of the lattice and disappears when the system restores C_{4} symmetry in the low temperature phase. In addition, we report the observation of a distinct electronic reconstruction that cannot be explained by the known electronic orders in the system.
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Affiliation(s)
- M Yi
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - A Frano
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
- Advanced Light Source, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
| | - D H Lu
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Y He
- Stanford Institute of Materials and Energy Sciences, Stanford University, Stanford, California 94305, USA
- Departments of Physics and Applied Physics, and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
| | - Meng Wang
- School of Physics, Sun Yat-Sen University, Guangzhou 510275, China
| | - B A Frandsen
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - A F Kemper
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - R Yu
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - Q Si
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - L Wang
- Institute for Solid State Physics, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
- Kirchhoff-Institute for Physics, Universitt Heidelberg, D-69120 Heidelberg, Germany
| | - M He
- Institute for Solid State Physics, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - F Hardy
- Institute for Solid State Physics, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - P Schweiss
- Institute for Solid State Physics, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - P Adelmann
- Institute for Solid State Physics, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - T Wolf
- Institute for Solid State Physics, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - M Hashimoto
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - S-K Mo
- Advanced Light Source, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
| | - Z Hussain
- Advanced Light Source, Lawrence Berkeley National Lab, Berkeley, California 94720, USA
| | - M Le Tacon
- Institute for Solid State Physics, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - A E Böhmer
- Institute for Solid State Physics, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - D-H Lee
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Z-X Shen
- Stanford Institute of Materials and Energy Sciences, Stanford University, Stanford, California 94305, USA
- Departments of Physics and Applied Physics, and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA
| | - C Meingast
- Institute for Solid State Physics, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - R J Birgeneau
- Department of Physics, University of California Berkeley, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
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6
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Thewalt E, Hayes IM, Hinton JP, Little A, Patankar S, Wu L, Helm T, Stan CV, Tamura N, Analytis JG, Orenstein J. Imaging Anomalous Nematic Order and Strain in Optimally Doped BaFe_{2}(As,P)_{2}. PHYSICAL REVIEW LETTERS 2018; 121:027001. [PMID: 30085755 DOI: 10.1103/physrevlett.121.027001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Indexed: 06/08/2023]
Abstract
We present the strain and temperature dependence of an anomalous nematic phase in optimally doped BaFe_{2}(As,P)_{2}. Polarized ultrafast optical measurements reveal broken fourfold rotational symmetry in a temperature range above T_{c} in which bulk probes do not detect a phase transition. Using ultrafast microscopy, we find that the magnitude and sign of this nematicity vary on a 50-100 μm length scale, and the temperature at which it onsets ranges from 40 K near a domain boundary to 60 K deep within a domain. Scanning Laue microdiffraction maps of local strain at room temperature indicate that the nematic order appears most strongly in regions of weak, isotropic strain. These results indicate that nematic order arises in a genuine phase transition rather than by enhancement of local anisotropy by a strong nematic susceptibility. We interpret our results in the context of a proposed surface nematic phase.
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Affiliation(s)
- Eric Thewalt
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Ian M Hayes
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - James P Hinton
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Arielle Little
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Shreyas Patankar
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Liang Wu
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Toni Helm
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Camelia V Stan
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Nobumichi Tamura
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - James G Analytis
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Joseph Orenstein
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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7
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Hussey NE, Buhot J, Licciardello S. A tale of two metals: contrasting criticalities in the pnictides and hole-doped cuprates. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:052501. [PMID: 29353812 DOI: 10.1088/1361-6633/aaa97c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The iron-based high temperature superconductors share a number of similarities with their copper-based counterparts, such as reduced dimensionality, proximity to states of competing order, and a critical role for 3d electron orbitals. Their respective temperature-doping phase diagrams also contain certain commonalities that have led to claims that the metallic and superconducting (SC) properties of both families are governed by their proximity to a quantum critical point (QCP) located inside the SC dome. In this review, we critically examine these claims and highlight significant differences in the bulk physical properties of both systems. While there is now a large body of evidence supporting the presence of a (magnetic) QCP in the iron pnictides, the situation in the cuprates is much less apparent, at least for the end point of the pseudogap phase. We argue that the opening of the normal state pseudogap in cuprates, so often tied to a putative QCP, arises from a momentum-dependent breakdown of quasiparticle coherence that sets in at much higher doping levels but which is driven by the proximity to the Mott insulating state at half filling. Finally, we present a new scenario for the cuprates in which this loss of quasiparticle integrity and its evolution with momentum, temperature and doping plays a key role in shaping the resultant phase diagram.
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Affiliation(s)
- N E Hussey
- High Field Magnet Laboratory (HFML-EMFL), Institute for Molecules and Materials, Radboud University, Toernooiveld 7, 6525 ED, Nijmegen, Netherlands
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8
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Bettinger JS. Comparative approximations of criticality in a neural and quantum regime. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 131:445-462. [PMID: 29031703 DOI: 10.1016/j.pbiomolbio.2017.09.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 09/01/2017] [Accepted: 09/04/2017] [Indexed: 06/07/2023]
Abstract
Under a variety of conditions, stochastic and non-linear systems with many degrees of freedom tend to evolve towards complexity and criticality. Over the last decades, a steady proliferation of models re: far-from-equilibrium thermodynamics of metastable, many-valued systems arose, serving as attributes of a 'critical' attractor landscape. Building off recent data citing trademark aspects of criticality in the brain-including: power-laws, scale-free (1/f) behavior (scale invariance, or scale independence), critical slowing, and avalanches-it has been conjectured that operating at criticality entails functional advantages such as: optimized neural computation and information processing; boosted memory; large dynamical ranges; long-range communication; and an increased ability to react to highly diverse stimuli. In short, critical dynamics provide a necessary condition for neurobiologically significant elements of brain dynamics. Theoretical predictions have been verified in specific models such as Boolean networks, liquid state machines, and neural networks. These findings inspired the neural criticality hypothesis, proposing that the brain operates in a critical state because the associated optimal computational capabilities provide an evolutionarily advantage. This paper develops in three parts: after developing the critical landscape, we will then shift gears to rediscover another inroad to criticality via stochastic quantum field theory and dissipative dynamics. The existence of these two approaches deserves some consideration, given both neural and quantum criticality hypotheses propose specific mechanisms that leverage the same phenomena. This suggests that understanding the quantum approach could help to shed light on brain-based modeling. In the third part, we will turn to Whitehead's actual entities and modes of perception in order to demonstrate a concomitant logic underwriting both models. In the discussion, I briefly motivate a reading of criticality and its properties as responsive to the characterization of tenets from Eastern wisdom traditions.
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Affiliation(s)
- Jesse Sterling Bettinger
- Johns Hopkins University, Center for Talented Youth, Baltimore, MD, United States; Center for Process Studies, Claremont, CA, United States.
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9
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Grinenko V, Iida K, Kurth F, Efremov DV, Drechsler SL, Cherniavskii I, Morozov I, Hänisch J, Förster T, Tarantini C, Jaroszynski J, Maiorov B, Jaime M, Yamamoto A, Nakamura I, Fujimoto R, Hatano T, Ikuta H, Hühne R. Selective mass enhancement close to the quantum critical point in BaFe 2(As 1-x P x ) 2. Sci Rep 2017; 7:4589. [PMID: 28676703 PMCID: PMC5496881 DOI: 10.1038/s41598-017-04724-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 05/15/2017] [Indexed: 11/09/2022] Open
Abstract
A quantum critical point (QCP) is currently being conjectured for the BaFe2(As1-x P x )2 system at the critical value x c ≈ 0.3. In the proximity of a QCP, all thermodynamic and transport properties are expected to scale with a single characteristic energy, given by the quantum fluctuations. Such a universal behavior has not, however, been found in the superconducting upper critical field H c2. Here we report H c2 data for epitaxial thin films extracted from the electrical resistance measured in very high magnetic fields up to 67 Tesla. Using a multi-band analysis we find that H c2 is sensitive to the QCP, implying a significant charge carrier effective mass enhancement at the doping-induced QCP that is essentially band-dependent. Our results point to two qualitatively different groups of electrons in BaFe2(As1-x P x )2. The first one (possibly associated to hot spots or whole Fermi sheets) has a strong mass enhancement at the QCP, and the second one is insensitive to the QCP. The observed duality could also be present in many other quantum critical systems.
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Affiliation(s)
- V Grinenko
- Institute for Solid State Physics, TU Dresden, 01069, Dresden, Germany. .,IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany. .,Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan.
| | - K Iida
- IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany.,Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan
| | - F Kurth
- Institute for Solid State Physics, TU Dresden, 01069, Dresden, Germany.,IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany
| | - D V Efremov
- IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany
| | - S-L Drechsler
- IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany
| | - I Cherniavskii
- Lomonosov Moscow State University, GSP-1, Leninskie Gory, Moscow, 119991, Russian Federation
| | - I Morozov
- IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany.,Lomonosov Moscow State University, GSP-1, Leninskie Gory, Moscow, 119991, Russian Federation
| | - J Hänisch
- IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany.,Karlsruhe Institute of Technology, Institute for Technical Physics, Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - T Förster
- Hochfeld-Magnetlabor Dresden (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, 01314, Dresden, Germany
| | - C Tarantini
- NHMFL, Florida State University, Tallahassee, FL, 32310, USA
| | - J Jaroszynski
- NHMFL, Florida State University, Tallahassee, FL, 32310, USA
| | - B Maiorov
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - M Jaime
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - A Yamamoto
- Department of Applied Physics, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo, 184-8588, Japan
| | - I Nakamura
- Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan
| | - R Fujimoto
- Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan
| | - T Hatano
- Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan
| | - H Ikuta
- Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan
| | - R Hühne
- IFW Dresden, Helmholtzstrasse 20, 01069, Dresden, Germany
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10
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Varma CM. Quantum-critical fluctuations in 2D metals: strange metals and superconductivity in antiferromagnets and in cuprates. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:082501. [PMID: 27411298 DOI: 10.1088/0034-4885/79/8/082501] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The anomalous transport and thermodynamic properties in the quantum-critical region, in the cuprates, and in the quasi-two dimensional Fe-based superconductors and heavy-fermion compounds, have the same temperature dependences. This can occur only if, despite their vast microscopic differences, a common statistical mechanical model describes their phase transitions. The antiferromagnetic (AFM)-ic models for the latter two, just as the loop-current model for the cuprates, map to the dissipative XY model. The solution of this model in (2+1)D reveals that the critical fluctuations are determined by topological excitations, vortices and a variety of instantons, and not by renormalized spin-wave theories of the Landau-Ginzburg-Wilson type, adapted by Moriya, Hertz and others for quantum-criticality. The absorptive part of the fluctuations is a separable function of momentum [Formula: see text], measured from the ordering vector, and of the frequency ω and the temperature T which scale as [Formula: see text] at criticality. Direct measurements of the fluctuations by neutron scattering in the quasi-two-dimensional heavy fermion and Fe-based compounds, near their antiferromagnetic quantum critical point, are consistent with this form. Such fluctuations, together with the vertex coupling them to fermions, lead to a marginal fermi-liquid, with the imaginary part of the self-energy [Formula: see text] for all momenta, a resistivity [Formula: see text], a [Formula: see text] contribution to the specific heat, and other singular fermi-liquid properties common to these diverse compounds, as well as to d-wave superconductivity. This is explicitly verified, in the cuprates, by analysis of the pairing and the normal self-energy directly extracted from the recent high resolution angle resolved photoemission measurements. This reveals, in agreement with the theory, that the frequency dependence of the attractive irreducible particle-particle vertex in the d-wave channel is the same as the irreducible particle-hole vertex in the full symmetry of the lattice.
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Affiliation(s)
- Chandra M Varma
- Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA
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11
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Eilers F, Grube K, Zocco DA, Wolf T, Merz M, Schweiss P, Heid R, Eder R, Yu R, Zhu JX, Si Q, Shibauchi T, Löhneysen HV. Strain-Driven Approach to Quantum Criticality in AFe_{2}As_{2} with A=K, Rb, and Cs. PHYSICAL REVIEW LETTERS 2016; 116:237003. [PMID: 27341252 DOI: 10.1103/physrevlett.116.237003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Indexed: 06/06/2023]
Abstract
The iron-based superconductors AFe_{2}As_{2} with A=K, Rb, Cs exhibit large Sommerfeld coefficients approaching those of heavy-fermion systems. We have investigated the magnetostriction and thermal expansion of this series to shed light on this unusual behavior. Quantum oscillations of the magnetostriction allow identifying the band-specific quasiparticle masses which by far exceed the band-structure derived masses. The divergence of the Grüneisen ratio derived from thermal expansion indicates that with increasing volume along the series a quantum critical point is approached. The critical fluctuations responsible for the enhancement of the quasiparticle masses appear to weaken the superconducting state.
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Affiliation(s)
- Felix Eilers
- Institut für Festkörperphysik, Karlsruher Institut für Technologie, 76021 Karlsruhe, Germany
| | - Kai Grube
- Institut für Festkörperphysik, Karlsruher Institut für Technologie, 76021 Karlsruhe, Germany
| | - Diego A Zocco
- Institut für Festkörperphysik, Karlsruher Institut für Technologie, 76021 Karlsruhe, Germany
| | - Thomas Wolf
- Institut für Festkörperphysik, Karlsruher Institut für Technologie, 76021 Karlsruhe, Germany
| | - Michael Merz
- Institut für Festkörperphysik, Karlsruher Institut für Technologie, 76021 Karlsruhe, Germany
| | - Peter Schweiss
- Institut für Festkörperphysik, Karlsruher Institut für Technologie, 76021 Karlsruhe, Germany
| | - Rolf Heid
- Institut für Festkörperphysik, Karlsruher Institut für Technologie, 76021 Karlsruhe, Germany
| | - Robert Eder
- Institut für Festkörperphysik, Karlsruher Institut für Technologie, 76021 Karlsruhe, Germany
| | - Rong Yu
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - Jian-Xin Zhu
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Qimiao Si
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Takasada Shibauchi
- Department of Advanced Materials Science, University of Tokyo, Kashiwa, Chiba 277-8561, Japan
- Department of Physics, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Hilbert V Löhneysen
- Institut für Festkörperphysik, Karlsruher Institut für Technologie, 76021 Karlsruhe, Germany
- Physikalisches Institut, Karlsruher Institut für Technologie, 76049 Karlsruhe, Germany
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12
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Hu D, Lu X, Zhang W, Luo H, Li S, Wang P, Chen G, Han F, Banjara SR, Sapkota A, Kreyssig A, Goldman AI, Yamani Z, Niedermayer C, Skoulatos M, Georgii R, Keller T, Wang P, Yu W, Dai P. Structural and Magnetic Phase Transitions near Optimal Superconductivity in BaFe2(As(1-x)Px)2. PHYSICAL REVIEW LETTERS 2015; 114:157002. [PMID: 25933332 DOI: 10.1103/physrevlett.114.157002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Indexed: 06/04/2023]
Abstract
We use nuclear magnetic resonance (NMR), high-resolution x-ray, and neutron scattering studies to study structural and magnetic phase transitions in phosphorus-doped BaFe2(As(1-x)P(x)2. Previous transport, NMR, specific heat, and magnetic penetration depth measurements have provided compelling evidence for the presence of a quantum critical point (QCP) near optimal superconductivity at x=0.3. However, we show that the tetragonal-to-orthorhombic structural (T{s}) and paramagnetic to antiferromagnetic (AF, TN) transitions in BaFe2(As(1-x)Px)2 are always coupled and approach T{N}≈T{s}≥T{c} (≈29 K) for x=0.29 before vanishing abruptly for x≥0.3. These results suggest that AF order in BaFe_{2}(As(1-x)Px)2 disappears in a weakly first-order fashion near optimal superconductivity, much like the electron-doped iron pnictides with an avoided QCP.
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Affiliation(s)
- Ding Hu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xingye Lu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Wenliang Zhang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Huiqian Luo
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shiliang Li
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of Quantum Matter, Beijing, China
| | - Peipei Wang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Genfu Chen
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Fei Han
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Shree R Banjara
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - A Sapkota
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - A Kreyssig
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - A I Goldman
- Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - Z Yamani
- Canadian Neutron Beam Centre, National Research Council, Chalk River, Ontario K0J 1P0, Canada
| | - Christof Niedermayer
- Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Markos Skoulatos
- Laboratory for Neutron Scattering, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Robert Georgii
- Heinz Maier-Leibnitz Zentrum, Technische Universität München, D-85748 Garching, Germany
| | - T Keller
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
- Max Planck Society Outstation at the Forschungsneutronenquelle Heinz Maier-Leibnitz (MLZ), D-85747 Garching, Germany
| | - Pengshuai Wang
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - Weiqiang Yu
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - Pengcheng Dai
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
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13
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Tokiwa Y, Bauer ED, Gegenwart P. Zero-field quantum critical point in CeCoIn5. PHYSICAL REVIEW LETTERS 2013; 111:107003. [PMID: 25166697 DOI: 10.1103/physrevlett.111.107003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 08/02/2013] [Indexed: 06/03/2023]
Abstract
Quantum criticality in the normal and superconducting states of the heavy-fermion metal CeCoIn5 is studied by measurements of the magnetic Grüneisen ratio ΓH and specific heat in different field orientations and temperatures down to 50 mK. A universal temperature over magnetic field scaling of ΓH in the normal state indicates a hidden quantum critical point at zero field. Within the superconducting state, the quasiparticle entropy at constant temperature increases upon reducing the field towards zero, providing additional evidence for zero-field quantum criticality.
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Affiliation(s)
- Y Tokiwa
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - E D Bauer
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - P Gegenwart
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
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14
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Yu R, Si Q, Goswami P, Abrahams E. Electron Correlation and Spin Dynamics in Iron Pnictides and Chalcogenides. ACTA ACUST UNITED AC 2013. [DOI: 10.1088/1742-6596/449/1/012025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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15
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Walmsley P, Putzke C, Malone L, Guillamón I, Vignolles D, Proust C, Badoux S, Coldea AI, Watson MD, Kasahara S, Mizukami Y, Shibauchi T, Matsuda Y, Carrington A. Quasiparticle mass enhancement close to the quantum critical point in BaFe2(As(1-x)P(x))2. PHYSICAL REVIEW LETTERS 2013; 110:257002. [PMID: 23829753 DOI: 10.1103/physrevlett.110.257002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 05/10/2013] [Indexed: 06/02/2023]
Abstract
We report a combined study of the specific heat and de Haas-van Alphen effect in the iron-pnictide superconductor BaFe2(As(1-x)P(x))2. Our data when combined with results for the magnetic penetration depth give compelling evidence for the existence of a quantum critical point close to x=0.30 which affects the majority of the Fermi surface by enhancing the quasiparticle mass. The results show that the sharp peak in the inverse superfluid density seen in this system results from a strong increase in the quasiparticle mass at the quantum critical point.
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Affiliation(s)
- P Walmsley
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
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16
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Ducatman S, Perkins NB, Chubukov A. Magnetism in parent iron chalcogenides: quantum fluctuations select plaquette order. PHYSICAL REVIEW LETTERS 2012; 109:157206. [PMID: 23102364 DOI: 10.1103/physrevlett.109.157206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Indexed: 06/01/2023]
Abstract
We analyze magnetic order in Fe chalcogenide Fe(1+y)Te, the parent compound of the high-temperature superconductor Fe(1+y)Te(1-x)Se(x). Experiments show that magnetic order in this material contains components with momentum Q(1)=(π/2,π/2) and Q(2)=(π/2,-π/2) in the Fe only Brillouin zone. The actual spin order depends on the interplay between these two components. Previous works assumed that the ordered state has a single Q (either Q(1) or Q(2)). In such a state, spins form double stripes along one of the diagonals breaking the rotational C(4) symmetry. We show that quantum fluctuations actually select another order-a double Q plaquette state with equal weight of Q(1) and Q(2) components, which preserves C(4) symmetry. We argue that the order in Fe(1+y)Te is determined by the competition between quantum fluctuations and magnetoelastic coupling.
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Affiliation(s)
- Samuel Ducatman
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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17
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Luo H, Zhang R, Laver M, Yamani Z, Wang M, Lu X, Wang M, Chen Y, Li S, Chang S, Lynn JW, Dai P. Coexistence and competition of the short-range incommensurate antiferromagnetic order with the superconducting state of BaFe(2-x)Ni(x)As2. PHYSICAL REVIEW LETTERS 2012; 108:247002. [PMID: 23004310 DOI: 10.1103/physrevlett.108.247002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Revised: 03/12/2012] [Indexed: 06/01/2023]
Abstract
Superconductivity in the iron pnictides develops near antiferromagnetism, and the antiferromagnetic (AF) phase appears to overlap with the superconducting phase in some materials such as BaFe(2-x)T(x)As2 (where T=Co or Ni). Here we use neutron scattering to demonstrate that genuine long-range AF order and superconductivity do not coexist in BaFe(2-x)Ni(x)As2 near optimal superconductivity. In addition, we find a first-order-like AF-to-superconductivity phase transition with no evidence for a magnetic quantum critical point. Instead, the data reveal that incommensurate short-range AF order coexists and competes with superconductivity, where the AF spin correlation length is comparable to the superconducting coherence length.
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Affiliation(s)
- Huiqian Luo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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